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Creating and managing an EGL context and surface is mandatory to perform GLES drawing and is very easy with Egloo. Classes that help in this start with the Egl prefix.

EGL context

The first thing to do is creating an EGL context. This can be done through the EglCore class:

val core = EglCore()
// At the end...

The core object will configure a GLES 2 or GLES 3 compatible EGL context, based on the presence of the EglCore.FLAG_TRY_GLES3 class. When you are done, the core should always be released.

The core object can also accept a shared context in the constructor, so that the new EGL context will share data with the old one.

After creation, EglCore can be used to create EGL surfaces.

EGL surfaces

Each EglCore object can be used to create one or more EglSurface, which represent the output where our GLES rendered data will be drawn. Egloo supports two types of surfaces.

After usage, all surfaces should be released with surface.release().


The EglWindowSurface uses a android.view.Surface or SurfaceTexture as output, two objects that can be considered system windows in Android. Anything drawn on this window will be passed to the given Surface or SurfaceTexture, for display or processing.

// Create window and make it the current EGL surface
val window = EglWindowSurface(core, output)

// Draw something
// ...

// Publish drawn content into output

The EglOffscreenSurface requires a width and a height in the constructor and corresponds to an EGL pixel buffer surface which does not depend on any platform window.

// Create pbuffer and make it the current EGL surface
val pbuffer = EglOffscreenSurface(core, 100, 100)

// Draw something
// ...

// Offscreen surfaces are single buffered, so
// you don't need to swapBuffers() to publish

GLSurfaceView utilities

When using the android.opengl.GLSurfaceView class, you can use two methods to control the EGL context initialization. Egloo provides static implementations of these:

// For GLES2...

// For GLES3...